Real-Time Study of the Adsorption and Grafting Process of Biomolecules by Means of Bloch Surface Wave Biosensors

Abstract

A combined label-free and fluorescence surface optical technique was used to quantify the mass deposited in binary biomolecular coatings. These coatings were constituted by fibronectin (FN), to stimulate endothelialization, and phosphorylcholine (PRC), for its hemocompatibility, which are two properties of relevance for cardiovascular applications. One-dimensional photonic crystals sustaining a Bloch surface wave were used to characterize different FN/PRC coatings deposited by a combination of adsorption and grafting processes. In particular, the label-free results permitted to quantitatively assess the mass deposited in FN adsorbed (185 ng/cm) and grafted (160 ng/cm). PRC binding to grafted FN coatings was also quantified, showing a coverage as low as 10 and 12 ng/cm for adsorbed and grafted PRC, respectively. Moreover, desorption of FN deposited by adsorption was detected and quantified upon the addition of PRC. The data obtained by the surface optical technique were complemented by water contact angle and X-ray photoelectron spectroscopy (XPS) analyses. The results were in accordance with those obtained previously by qualitative and semiquantitative techniques (XPS, time-of-flight secondary ion mass spectrometry) on several substrates (PTFE and stainless steel), confirming that grafted FN coatings show higher stability than those obtained by FN adsorption.

Effects of Reabsorption due to Surface Concentration in Highly Resonant Photonic Crystal Fluorescence Biosensors

“…Similarly to our previous work with different molecular species, we observe experimentally that the incubation time is sufficient to obtain an organic Cy7-VG20 layer assembled at the 1DPC surface, bound to the hydroxy groups generated after piranha cleaning by van der Waals forces. We observed much weaker effects if the 1DPC were not treated with the piranha solution before incubation.…”

“…For every series of measurements, we used always the same BSW bio-chip that did not show any degradation after repeated piranha cleaning (up to 20 times). Similarly to our previous work with different molecular species [28], experimentally we observe that the incubation time is sufficient to obtain an organic Cy7-VG20 layer assembled at the 1DPC surface, bound to the hydroxy-groups generated after piranha by Van der Waals forces. We observed much weaker effects if the 1DPC were not treated with the piranha solution before The Journal of Physical Chemistry incubation.…”

Lossy mode resonance sensors based on lateral light incidence in nanocoated planar waveguides

“…By introducing light with different angles of incidence, a surface plasmon polariton is excited in the metal–dielectric interface at a specific angle range, something that is also observed as a function of wavelength. Bloch surface waves can also be obtained with the Kretschmann configuration and be used for sensing 3 .…”

Nanoparticle-Based FM-MCF LSPR Biosensor With Open Air-Hole

“…Optical biosensors have shown good performance in detecting biological systems and have promoted major advances in clinical diagnosis, drug discovery, food safety, and environmental monitoring (Chiavaioli et al, 2017a;Zanchetta et al, 2017;Sinibaldi et al, 2018;Min Y, 2020) This is due to the high sensitivity, anti-interference, stability, low noise, and other advantages of optical signals.…”